On the evolutionary edge of migration as an assortative mating device

In a haystack-type representation of a heterogeneous population that is evolving according to a payoff structure of a prisoner's dilemma game, migration is modeled as a process of 'swapping' individuals between heterogeneous groups of constant size after a random allocation fills the haystacks, but prior to mating. Migration is characterized by two parameters: an exogenous participation-in-migration cost (of search, coordination, movement, and arrangement-making) which measures the migration effort, and an exogenous technology-of coordinating and facilitating movement between populated haystacks and the colonization of currently unpopulated haystacks-which measures the migration intensity. Starting from an initially heterogeneous population that consists of both cooperators and defectors, a scenario is postulated under which 'programmed' migration can act as a mechanism that brings about a long-run survival of cooperation.